The catalytic core of DEMETER guides active DNA demethylation in Arabidopsis

• DOI: 10.1073/pnas.1907290116
• Publication Date: 2019-08-13T21:05:50Z
• Authors: Changqing Zhang; Yu-Hung Hung; Hyun Jung Rim; Dapeng Zhang; Jennifer M. Frost; Hosub Shin; Hosung Jang; Fang Liu; Wenyan Xiao; Lakshminarayan M....; L. Aravind; Xiang-Qian Zhang; Robert L. Fischer; Jin Hoe Huh; Tzung-Fu Hsieh
• Keywords: DNA demethylation; Epigenomics; Euchromatin; Demethylation

The Arabidopsis DEMETER (DME) DNA glycosylase demethylates the maternal genome in central cell prior to fertilization and is essential for seed viability. DME preferentially targets small transposons that flank coding genes, influencing their expression initiating plant gene imprinting. also intergenic heterochromatic regions, but how it recruited these differing chromatin landscapes unknown. C-terminal half of consists 3 conserved regions required catalysis vitro. We show this catalytic core guides active demethylation at endogenous targets, rescuing dme developmental genomic hypermethylation phenotypes. However, without N terminus, heterochromatin significantly impeded, abundant CG-methylated genic sequences are ectopically demethylated. Comparative analysis revealed N-terminal domains present only flowering plants, whereas domain architecture DME-like proteins nonvascular plants mainly resembles core, suggesting might represent ancestral form 5mC found lineages. propose a bipartite model protein action suggest terminus was acquired late during land evolution improve specificity facilitate targets.